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Ir sensors not working

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  • Member since
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Ir sensors not working
Posted by ripgp30 on Sunday, May 12, 2019 2:19 PM

Having a problem installing ir sensors they will not work

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Posted by RR_Mel on Sunday, May 12, 2019 2:28 PM

That’s not much info or are you just complaining about IR detection?
 
 
EDIT:
 
LED room lighting can ding the IR sensors.  I have LED replacement bulbs in my garage and the IR sensors can see the IR emitted from the overhead lighting.
 
 
Mel
 
 
My Model Railroad   
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
 
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Posted by MisterBeasley on Sunday, May 12, 2019 2:54 PM

I tried IR detectors for my grade crossing signals, but finally gave up.  The visible light ones work well enough, even in dim light, almost but not quite really dark.

It takes an iron man to play with a toy iron horse. 

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Posted by ripgp30 on Sunday, May 12, 2019 2:58 PM

If I hold my hand over them they work fine

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Posted by RR_Mel on Sunday, May 12, 2019 3:36 PM

I take it that they are reflective and don’t respond to rail traffic.  Is your system home brew or purchased?
 
I’m using a Mel made IR beam break system that has worked very well for several years.  I’m currently working on a new Signaling system using an Arduino MEGA and FC-51 IR detectors.  The FC-51 is a reflective type and requires more detection modules than the beam break type.
 
The FC-51 is very low cost at 50¢ each off eBay.  The published specs on the FC-51 is 11” but the best they will do for me is 3½” to 4”.  I’m installing them on 14” centers.  Bulk cost for the FC-51 is 50 for a bit under $20.
 
I have 8 installed between the ties and so far they work great.
 
They will work as beam break by remoting the emitter at 48" but that inverts the detector output
 
 
 
Mel
 
 
My Model Railroad   
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
 
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Posted by gregc on Sunday, May 12, 2019 5:32 PM

ripgp30
If I hold my hand over them they work fine

how high above them do you hold your hand?   ?

greg - Philadelphia & Reading / Reading

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Posted by ripgp30 on Sunday, May 12, 2019 6:55 PM
one half to three quarter inch
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Posted by gregc on Sunday, May 12, 2019 7:54 PM

the angular sensitivity can be somewhat narrow.   for close distances, both emitter and sensor may need to be tilted toward one another. 

Presumably both emitter and detector operate at the same wavelength. 

ironically, some sensors require heat shrink tubing to limit their direction to avoid false detections.

greg - Philadelphia & Reading / Reading

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Posted by BigDaddy on Monday, May 13, 2019 4:10 PM

Mel weren't you having trouble with interference of overhead LED lighting?

Henry

COB Potomac & Northern

By the Chesapeake Bay

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Posted by RR_Mel on Monday, May 13, 2019 9:29 PM

Henry
 
Yes.  When replaced my 8’ fluorescent tube lighting with 8’ LEDs the IR detectors could see some of the LED IR.  It only changed the noise level a bit and I tweaked the sensitivity pots and that took care of it.
 
I would think a lot of LED lighting mite be a problem for IR detection.  The LED replacements are much brighter than the old Fluorescent lights.
 
 
Mel
 
 
My Model Railroad   
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
 
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Posted by RR_Mel on Wednesday, May 15, 2019 11:01 AM

ripgp30
 
I’m just curious, what IR detector are you using?  I’m using the Arduino FC-51 modules.  Their advertised specs say 2~30cm but out of 10 the best I can get out of one is 10cm or about 4”.
 
I bought another batch (50 for $20) and they are about the same as the first batch.
 
I they come with 5mm emitters and sensors and I have swapped them out with 3mm sensors and they seem to have a bit more range.  The reason for swapping them out is the 3mm fit better between the ties.
 
 
 
I remoted the 3mm sensors to make installation and maintenance (adjustment) easier.  I drill a 9/64” hole between the ties and elongate it so that the pair of sensors can slip in flush with the cork roadbed or the bottom of the ties.  I paint the inside of the hole flat black (I use SP black ballast) then using Amazing Goop sparingly glue them in being careful to avoid getting glue on the top of the sensors.  Using a small amount of Goop allows them to be removed easily if needed.
 
For hidden track I just mount a three pin Arduino female connector flush with the plywood parallel to the track 2” off center and plug the FC-51 modules in facing the track.  That puts the sensors at about coupler level.
 
 
I don’t replace the sensors that are not between the ties unless I need to remote the them.  I try to keep everything as simple as possible.
 
 
 
Mel
 
 
My Model Railroad   
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
 

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